[PATCH] Fix PR38826 and PR38477

Richard Guenther rguenther@suse.de
Wed Jan 14 10:01:00 GMT 2009


On Tue, 13 Jan 2009, Daniel Berlin wrote:

> How is this not going to become the same problem with IPA mode?
> ISTM we should probably move the computation of call clobbering to be
> more independent of the rest of PTA.

You cannot decouple them, as a call may clobber (and thus affects
the points-to sets) of all reachable memory.  Unless you mark all
memory that had its address taken as pointing to anything after each call,
of course.

> So, after talking with some others who work on points-to algorithms,
> we've all agreed the proper solution to this problem is to mark all
> nodes in a structure as indirect when the structure is address taken
> (IE set graph->direct_nodes[n] false for each node). The notion of an
> indirect node is that it can be referenced without using it's
> syntactic name, which is exactly what is happening here.
> This only affects the offline optimization portion.
> It will cause slightly less offline optimization, but that is fixable
> in other ways.

Ok, I will try to do this.

> If you'd like to disable field-sensitivity, i'd rather see us do that
> as a separate patch, since the bug you are fixing would still remain
> if you go this route.
> :)

Agreed.

Richard.



More information about the Gcc-patches mailing list